The present invention relates to an improved hold-down assembly for a shear of the type used for shearing pieces from an elongated metal member.
By way of background, there are shears in existence known as bar or billet shears which shear pieces of metal from an elongated metallic member. Shears of this type are shown in U.S. Pat. No. 3,152,499 and No. 3,908,496. In both of the foregoing shears, the workpiece, that is, the portion of an elongated member which is to be sheared therefrom, is supported by a work support member while the portion of the elongated member adjacent thereto is held down by a hold-down member. Thereafter, the movable knife of the shear is caused to approach the fixed knife to sever the workpiece from the end of the elongated member. In machines of the foregoing type, the hold-down is mounted at the front of the machine. The rear end of the machine usually mounts a back gauge assembly against which the elongated member abuts so as to gauge the length of the workpiece to be sheared. In addition, at the rear of the machine there usually is a chute for guiding workpieces into a bin, which is also located at the rear of the machine.
In machines of the foregoing type, the fixed and movable knives have to be removed periodically for sharpening. In addition, when the knives are reinserted in the machine, they have to be adjusted for proper clearance. Furthermore, the knives must be inspected periodically and access to the area at which the knives are located must be had periodically. However, in the past, the replacement of knives from the rear of the machine was awkward and difficult in view of the fact that access was blocked by the back gauge, chute and bin, mentioned above. Furthermore, access from the front of the machine was blocked by the hold-down structure. As a result, replacement and adjustment of the knives was not only very difficult, because of the limited access, but was also very time-consuming and required that the machine be out of operation for a relatively long period of time. It is with overcoming the foregoing deficiencies in prior art shearing machines that the present invention is concerned.